bat script that gets the user hive of a terminal user profile loged on how?

in our company we have a citrix PS4 farm with windows 2000 terminal service..
and i want to set a reg keyvalue setting of the terminal server user that launc the application so it is stored in the user (current user) hive. the problem is that only domain admins have write rights in that key of the current user hive.. so I want to set it with subInAcl or somthing that can do the trick but I don’t know how to get the userhive of the profile out so I can use it in the bat file for setting the key permission.. because SubInAcl have to know witch Hive to set it for.. does it make sence ?? how can I get it.. is it possible